Manufacture of polycarbonates

Abstract

A method of producing a polycarbonate is provided. In an embodiment of the present invention the method includes the steps of: (i) introducing to a melt polymerization reactor system a reaction mixture having a first dihydroxy compound and an acid stabilizer, a carbonate source, and a polymerization catalyst system containing K 2 HPO 4 ; and (ii) allowing the reaction mixture to polymerize thereby forming polycarbonate.

1. A method of producing a polycarbonate comprising the steps of,
 (i) introducing to a melt polymerization reactor system comprising a polymerization reactor operating under melt polymerization conditions, a reaction mixture comprising: 
 an acid stabilizer and a first dihydroxy compound selected from the group consisting of catechol, resorcinol, hydroquinone, butyl hydroquinone, methyl hydroquinone, DMBPC, biphenol, o,o-biphenol, 2,2-dihydroxynaphtalene, and ortho-methyl BPA, 
 an activated diarylcarbonate, 
 and a polymerization catalyst system comprising a first catalyst compound having the structure:
   M p H q Q 
 wherein Q is phosphate, sulfate, phosphite, sulfite, thiosulfate, or thiophosphate; H is hydrogen; M is an alkali metal, an alkali earth metal, or (NH 4 ); and p and q are independently 1 or 2, and wherein the first catalyst compound is present in an amount sufficient to catalyze a polymerization reaction between the free hydroxyl ends of the first dihydroxy compound and the activated diarylcarbonate, and 
 
 (ii) allowing the reaction mixture to polymerize thereby forming polycarbonate. 
 
     
     
       2. The method of  claim 1 , wherein Q is phosphate or sulfate, and M is an alkali metal or alkali earth metal. 
     
     
       3. The method of  claim 2 , wherein the first catalyst compound comprises a compound selected from the group consisting of K 2 HPO 4 , KNaHPO 4 , and Na 2 HPO 4 . 
     
     
       4. The method of  claim 1 , wherein the activated diarylcarbonate comprises bismethylsalicylcarbonate. 
     
     
       5. The method of  claim 1 , wherein the polycarbonate is a copolycarbonate and wherein the method further comprises the step of adding a second dihydroxy compound to the reaction mixture. 
     
     
       6. The method of  claim 1 , wherein the first catalyst compound is present in the reaction mixture such that the molar ratio of moles of the first catalyst compound to the total moles of dihydroxy compound is between 1×10 −4  and 1×10 −8 . 
     
     
       7. The method of  claim 6 , wherein the first catalyst compound is present in the reaction mixture such that the molar ratio of moles of the first catalyst compound to the total moles of dihydroxy compound is between 1×10 −4  and 1×10 −7 . 
     
     
       8. The method of  claim 6 , wherein Q is phosphate or sulfate, and M is an alkali metal or alkali earth metal. 
     
     
       9. The method of  claim 8 , wherein the first catalyst compound comprises a compound selected from the group consisting of K 2 HPO 4 , KNaHPO 4 , and Na 2 HPO 4 . 
     
     
       10. The method of  claim 1 , wherein the polymerization catalyst system further comprises a second catalyst compound comprising: quaternary ammonium compound, a quaternary phosphonium compound, or both a quaternary ammonium compound and a quaternary phosphonium compound. 
     
     
       11. The method of  claim 1 , further comprising the step of:
 (iii) removing the polycarbonate from the melt polymerization reactor system. 
 
     
     
       12. The method of  claim 11 , wherein at least one of steps (i), (ii), and (iii) is performed continuously. 
     
     
       13. The method of  claim 11 , wherein all of steps (i), (ii), and (iii) are performed continuously. 
     
     
       14. A method of producing a polycarbonate comprising the steps of,
 (i) introducing to a melt polymerization reactor system comprising a polymerization reactor operating under melt polymerization conditions, a reaction mixture comprising a first dihydroxy compound and an acid stabilizer, a carbonate source, and a polymerization catalyst system comprising a first catalyst compound having the structure:
   M p H q Q 
 wherein Q is phosphate, sulfate, phosphite, sulfite, thiosulfate, or thiophosphate; H is hydrogen; M is an alkali metal, an alkali earth metal, or (NH 4 ); and p and q are independently 1 or 2, and wherein the first catalyst compound is present in an amount sufficient to catalyze a polymerization reaction between the free hydroxyl ends of the first dihydroxy compound and the carbonate source, and 
 
 (ii) allowing the reaction mixture to polymerize thereby forming polycarbonate. 
 
     
     
       15. The method of  claim 14 , wherein Q is phosphate or sulfate, and M is an alkali metal or alkali earth metal. 
     
     
       16. The method of  claim 15 , wherein the first catalyst compound comprises a compound selected from the group consisting of K 2 HPO 4 , KNaHPO 4 , and Na 2 HPO 4 . 
     
     
       17. The method of  claim 14 , wherein the first dihydroxy compound comprises a compound having the structure, 
       
         
           
           
               
               
           
         
         wherein each R 15  is independently at each occurrence a hydrogen atom, halogen atom, nitro group, cyano group , C 1 -C 20  alkyl, C 4 -C 20  cycloalkyl radical, C 4 -C 20  aryl radical, and d is an integer from 0 to 4. 
       
     
     
       18. The method of  claim 17 , wherein the first dihydroxy compound is selected from the group consisting of catechol, resorcinol, hydroquinone, butyl hydroquinone, and methyl hydroquinone. 
     
     
       19. The method of  claim 14 , wherein the first dihydroxy compound is selected from the group consisting of DMBPC, biphenol, o,o-biphenol, 2,2-dihydroxynaphtalene, and ortho-methyl BPA. 
     
     
       20. The method of  claim 14 , wherein the carbonate source comprises bismethylsalicylcarbonate. 
     
     
       21. The method of  claim 14 , wherein the polycarbonate is a copolycarbonate and wherein the method further comprises the step of adding a second dihydroxy compound to the reaction mixture. 
     
     
       22. The method of  claim 14 , wherein the first catalyst compound is present in the reaction mixture such that the molar ratio of moles of the first catalyst compound to the total moles of dihydroxy compound is between 1×10 −4  and 1×10 −8 . 
     
     
       23. The method of  claim 22 , wherein the first catalyst compound is present in the reaction mixture such that the molar ratio of moles of the first catalyst compound to the total moles of dihydroxy compound is between 1×10 −4  and 1×10 −7 . 
     
     
       24. The method of  claim 22 , wherein Q is phosphate or sulfate, and M is an alkali metal or alkali earth metal. 
     
     
       25. The method of  claim 24 , wherein the first catalyst compound comprises a compound selected from the group consisting of K 2 HPO 4 , KNaHPO 4 , and Na 2 HPO 4 . 
     
     
       26. The method of  claim 14 , wherein the polymerization catalyst system further comprises a second catalyst compound comprising: quaternary ammonium compound, a quaternary phosphonium compound, or both a quaternary ammonium compound and a quaternary phosphonium compound. 
     
     
       27. The method of  claim 14 , further comprising the step of:
 (iii) removing the polycarbonate from the melt polymerization reactor system. 
 
     
     
       28. The method of  claim 27 , wherein at least one of steps (i), (ii), and (iii) is performed continuously. 
     
     
       29. The method of  claim 27 , wherein all of steps (i), (ii), and (iii) are performed continuously.